The place where Christopher Hitchens spent his last few weeks was hardly bookish, but he made it his own. Close to downtown Houston, Texas is the medical centre, a cluster of high-rises like La Défense of Paris, or the City of London, a financial district of a sort, where the common currency is illness. This complex is one of the world's great concentrations of medical expertise and technology. Its highest building, 40 or 50 storeys up, denies the possibility of a benevolent god – a neon sign proclaims from its roof a cancer hospital for children. This "clean-sliced cliff", as Larkin puts it in his poem about a tower-block hospital, was right across the way from Christopher's place – which was not quite as high, and adults only.

No man was ever as easy to visit in hospital. He didn't want flowers and grapes, he wanted conversation, and presence. All silences were useful. He liked to find you still there when he woke from his frequent morphine-induced dozes. He wasn't interested in being ill, the way most ill people are. He didn't want to talk about it.

When I arrived from the airport on my last visit, he saw sticking out of my luggage a small book. He held out his hand for it – Peter Ackroyd's London Under, a subterranean history of the city. Then we began a 10-minute celebration of its author. We had never spoken of him before, and Christopher seemed to have read everything. Only then did we say hello. He wanted the Ackroyd, he said, because it was small and didn't hurt his wrist to hold. But soon he was making pencilled notes in its margins. By that evening he'd finished it.